Yea, it's likely a font issue. This[1] is what my font looks like, which is quite readable to me but i can't get much smaller (for me personally). Each pane fits ~85 chars (not including the vim sidebars/etc), so it's quite perfect for two panels.
Note that OSX by default has some type of feature that reduces the realestate you have available.. don't ask me to explain it, i haven't really used it much.
Basically, with the Retina monitors, the resolution is actually too high for a lot of scenarios. You end up with tiny fonts, tiny icons, etc. So they somehow sample/zoom the sizes so that you get both really crisp renders but with very few real pixels on screen.
This may be what is causing you to be surprised that i am still having issues with a high resolution Retina screen. But, turning it off would be effectively the same thing as just turning my iTerm2 fontsize to ~8-10 or something tiny, allowing me to fit three panes.
Note that OSX by default has some type of feature that reduces the realestate you have available.. don't ask me to explain it, i haven't really used it much.
Basically, with the Retina monitors, the resolution is actually too high for a lot of scenarios. You end up with tiny fonts, tiny icons, etc. So they somehow sample/zoom the sizes so that you get both really crisp renders but with very few real pixels on screen.
This may be what is causing you to be surprised that i am still having issues with a high resolution Retina screen. But, turning it off would be effectively the same thing as just turning my iTerm2 fontsize to ~8-10 or something tiny, allowing me to fit three panes.
[1]: http://imgur.com/MBvoEJd